The problem of acute osteomyelitis in children is of special importance among the inflammatory diseases of musculoskeletal system, due to infectious conditions arising in the body and spreading to the bone tissue caused by impaired immune regulation, first of all, concerning neutrophilic granulocytes. Of interest is studying the subsets of neutrophilic granulocytes arising when the cells are involved into the inflammatory process in acute pediatric osteomyelitis, and determining the opportinity to influence the level of receptor expression aiming for correction of their functions. The purpose of our study was to evaluate the effect of hexapeptide arginyl-alpha-aspartyl-lysyl-valyl-tyrosyl-arginine on the altered phenotype of neutrophilic granulocytes in children with acute osteomyelitis using an in vitro experimental model. We examined the peripheral blood samples from children with acute hematogenous or post-traumatic osteomyelitis at the age of 10 to 17 years (n = 12) upon their admission to the hospital, and from healthy children (n = 7). Blood samples from children with acute osteomyelitis were incubated with hexapeptide (10-6 g/L) for 60 min, at 37 C. The content of neutrophilic granulocyte subsets (CD16+CD62L+CD11b+CD63- and CD16+CD62L+CD11b+CD63+), expression density of appropriate membrane receptors were assessed by flow cytometric technique (FC 500 Beckman Coulter, USA). Phagocytic function was studied by assessing the degree of completed phagocytosis of S. aureus. It was found that, in acute osteomyelitis, a 8.5-fold increased proportion of activated CD16+CD62L+CD11b+CD63+NG subset with the CD16brightCD62LbrightCD11bbrightCD63dimNG phenotype was revealed, along with a decrease in the CD16+CD62L+CD11b+CD63-NG subset and changes in the CD16dimCD62LbrightCD11bmidCD63- NG phenotype as compared with reference indexes of healthy children. At the same time, an increased number of actively phagocytic cells was noted, however, with decreased indexes characterizing capture and digestion of the bacterial antigen. In the in vitro experiments, the tested hexapeptide was shown to modulate the phenotypes of both studied subsets (CD16brightCD62LmidCD11bmidCD63- and CD16midCD62LmidCD11bmidCD63dimNG), thus promoting restoration of the receptor expression levels to the reference group values, as well as phagocytic activity, in terms of uptake and digestive capacity of microbial cells. Thus, the dominance of a diagnostically significant activated CD16+CD62L+CD11b+CD63+ neutrophil subset with the CD16brightCD62LbrightCD11bbrightCD63dimNG phenotype was found in acute osteomyelitis in children. The results of in vitro studies have shown that the hexapeptide caused phenotypic modulation of the CD16+CD62L+CD11b+CD63- neutrophils, and CD16+CD62L+CD11b+CD63+NG subsets, along with recovery of their phagocytic activity. In the future, our results may provide a basis for the development of new effective therapeutic regimens.
Acute peritonitis (AP) is among the most frequent and severe conditions in pediatric abdominal surgery. Due to development of antibiotic resistance and increasing number of atypical infectious and inflammatory diseases (IIDs), a lot of specialists suggest combined treatments for these patients which should include not only surgical and etiotropic approaches, as well as therapy aimed at correction of functional defects of immunity. Neutrophilic granulocytes (NGs) reepresent a unique population of cells of primary anti-infectious immune response. Functional NG defects in pediatric AP play a leading role in development, prevalence, severity of peritoneal inflammation, and response to the therapy. Special role is given to functionally significant NG subsets responsible for triggering and implementation of phagocytosis and microbicidal properties of NG in purulent lesions and inflammatory process in children. There is an urgent need for development of new approaches to targeted immunomodulatory therapy in order to correct the NG dysfunction. The aim of the present study was to arrange the programs of immunomodulatory therapy after surgical treatment of immunocompromised children with various forms of acute peritonitis followed by subsequent evaluation of its clinical and immunological efficacy. The study included 12 immunocompromised children aged 5-12 years with different clinical course of acute peritonitis. The study group 1 included patients with local nonrestricted AP; study group 2 involved children with diffuse AP. The comparison groups consisted of 6 children who received standard therapy, i.e., clinical comparison groups 1 and 2, matched for sex, age and diagnosis. A control group consisted of 18 conditionally healthy children at similar age. Clinical examination included collection of the patient’s history, complaints, objective examination and clinical course assessment of the underlying disease. Immunological study included determination of receptor, phagocytic and microbicidal activity of NCs; assessment of NC subpopulations by their numbers and phenotype using flow cytometry, i.e., the cells co-expressing CD64, CD16, CD32, CD11b, with testing density of these membrane receptors by the MFI approach. Targeted immunomodulatory therapy programs were applied for treatment of children with unrestricted local and diffuse AP, taking into account clinical features of AP, as well as changes in number and phenotype of NC subpopulations, and impairment of their effector function. The standards of postsurgical treatment in the children with various forms of AP included different courses of treatment with Imunofan (Hexapeptide – arginyl-alpha-aspartyl-lysyl-valyl-tyrosyl-arginine; HP) using different schedules and duration. We have shown high clinical and immunological efficiency of these therapeutic programs. Thus, reversal of adequate NG functioning was observed, including positive rearrangements of negatively transformed functional NG subpopulations. In this respect, a positive clinical effect was noted in children with atypical AP with various clinical courses, i.e., absence of postsurgical complications, rapid regression of intoxication signs, normalization of body temperature, reduced volume of antibiotic therapy and shorter hospitalization terms.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.